Two-stage Technology Research Articles

Natural Childbirth after the Previous Caesarian Section is a Solved Problem

Тhe rapid increase in the frequency of сesarian section (CS) observed in recent years (up to 60% in some countries) is alarming and reduces the reproductive potential of the population. The operated uterus remains the main indication for CS (up to 40%). This is the factor which may allow reducing the frequency of the CS by subsequent delivering through the birth canal. A comparative analysis of maternal and neonatal outcomes enabled the authors to develop a two-stage delivery technology for patients with a caesarean scar, including the usage of the programmed delivery method. The presented algorithm confirmed the validity of vaginal delivery in such patients, and reduced the number of complications up to 4 times. Neonatal morbidity in children born through the birth canal in such patients was comparable to physiological birth.

Regression mathematical model of two-stage combined electrical technology of high-temperature convective drying and ozone-air grain processing

Large production of cereal crops in Russia in 2014-2018 (100-130 million tons) imply the need to dry 10-30 % of the crop collected annually in the country to ensure its quantitative and qualitative preser-vation. The main way to reduce the excess moisture of grain in the Russian Federation is high-temperature convective drying, but it refers to very energy-intensive technological operations and, therefore, is very expensive. In the context of the constant increase in energy prices in the Russian economy, the country's agricultural producers face the primary task of increasing the profitability of the grain industry, within which it is necessary to reduce material costs at all stages of production, including through the creation of new high-intensity energy-saving technologies and technical means for drying grain raw materials. The authors have developed a two-stage technology of high-temperature convective and ozone-air grain drying that meets these requirements. In the article, based on the analysis of the parametric scheme of the convective-ozone-air moisture removal method, compiled taking into account the conditions and possibilities of conducting experimental studies of the process at the industrial drying unit «ELEKTA-1» of small productivity, the optimization parameters of this process are defined, which are: reduction of the drying time and the total reduction in energy consumption, in addition, the main factors varied in the ex-periments are highlighted: the initial moisture content of the grain, the amount of ozone supply to 1 m3 of grain and time spent on moisture removal. Second-order regression mathematical models for the convec-tive-ozone-air drying of barley grain with different initial humidity (30, 25 and 20 %) have been developed and their statistical significance has been evaluated. An analysis of the experimental data of the combined drying options studied at 6 % moisture removal for one cycle of processing the grain material revealed the following parameters of the efficiency of the methods of convective ozone-air moisture removal: when drying grain with an initial humidity of 30 %, the process duration decreased by 28 % and the total energy consumption decreased amounted to 33-43 %; when drying grain with a moisture content of 25 %, the duration of the process is reduced by 19 %, energy consumption by 24-35 %; and when drying grain with a moisture content of 20 %, the duration of the process is reduced by 30-35 %, energy consumption by 35-40 %.

Modifying epoxy polymers by cyclic carbonates of epoxidated plant oils

Introduction. Application of renewable raw materials for manufacturing non-toxic components of polymer materials is of great practical interest. Cyclic carbonates on the base of epoxidated rubber tree oil could be seen as a promising alternative of fossil fuels. The ability of compounds containing cyclic carbonates to interact with primary amines and to form urethane and hydroxyl groups makes them rather efficient modifiers of amine-toughened epoxy compounds on the base of low-molecular diane oligomers. Introduction of cyclic carbonates enhances impact behavior of epoxy materials as well as their adhesion and strength properties. Materials and methods. Epoxy resin ED-20 was used for the research, as a cross-linking agent for cold toughening aminealkylphenol AF-2 was used; cyclic carbonates of epoxidated soy oils and rubber tree oil were applied as modifiers. Adhesional strength of bond joints has been determined in compliance with the GOST 28840-90, abrasive hardness of epoxy compound samples has been tested by the vertical optical caliper IZV-1. Results. When applying two-stage technology for obtaining epoxy cyclic carbonate compounds, there has been appeared a significant increase of adhesion to aluminum. This effect could be even more noticeable with increasing temperature during the stage of mixture of the amine toughener with the cyclic carbonate modifier. High viscosity of cyclic carbonate modifiers complicates the process of mixing components of the epoxy compound and correspondingly its application as a backing of glues and linings. The authors researched cyclic carbonates of epoxidated soy oil with various averaged functionality as modifiers. Application of epoxy materials CESO-75 as a modifier has proven to be more forward-thinking for the reasons of cost-efficiency and for operating and technological properties. CESO lowers the coefficient of static friction for epoxy materials together with enhancing their abrasion hardness. Conclusions. Cyclic carbonates of epoxidated plant oils (soy oil and rubber tree oil) as rather efficient non-toxic modifiers of epoxy polymers are of practical interest. They are produced on the base of annually renewable plant raw materials. Their application enables to enhance abrasion hardness and adhesion properties of epoxy compounds and also improve their antifriction properties.

Thermal Insulation Materials With High-Porous Structure Based on the Soluble Glass and Technogenic Mineral Fillers

The raw material mixture from the silicon-like technogenic component the ash-removal of thermal power plants and the preparation methods of waterproof porous heat-insulated materials wide usage for raw mass hot foaming powdered two-stage technology are developed. The development uses the polyfunctional properties of liquid glass as a) the binder component; c) breeder; c) the speed regulator of the clamping mass hardenin. Its optimized version begins to solidify at its usual temperature from the moment its "reproduction" is soluble glass and forms a paste-shaped cake with a set of properties necessary for the next fragmentation. The proposed formulation allows compositions processing in various ways, with the formation of granular heat-insulating fillers, materials for thermal insulation in complex structures, slab and shell-like types of thermal insulation materials. The task is set, depending on the goals and features of the tasks being solved; it is possible to conduct several different methods at the final stages of their obtaining. Two stages of the recycling process determine the character and behavior of the rare-glass composite systems constituent components during heat treatment, their strong adhesion to most structural materials and the need to solve billets easy removal problem from the molding unit. Study results can be used in the field of building materials production, in particular porous artificial products, in obtaining granular insulating material and light aggregate for concrete industrial and civil construction, in thermal engineering as thermal insulation, etc.

Process constraints in sustainable bio-hythane production from wastewater: Technical note

The economy of an industrialized country is greatly dependent on fossil fuels. However, these non-renewable sources of energy are nearing the brink of extinction and which have caused serious adverse impacts on the environment. Hydrogen has emerged as a promising alternative and also has the highest calorific value. Bio-hythane is a hydrogen-methane blend can be produced from different organic substrates by two sequential anaerobic stages: a dark fermentation step followed by a second an anaerobic digestion step, for hydrogen and methane production, respectively. Bio-hythane is considered to be promising approach in sustainable energy sector. The advantages of two-stage technology include; high organic removal, high energy recovery and environment friendly. However, current efforts to recover bio-hythane energy from waste are still at bench scale level. The technical constraints in the fermentation must be removed for the indispensable bio-hythane recovery from waste. This short technical note highlights the two-stage fermentation and the technical barriers to be addressed for bio-hythane scale up from waste.

Two-Stage Technology for Palm Oil Fractionation for Production of Cocoa Butter Substitutes

Two-Stage Technology for Palm Oil Fractionation for Production of Cocoa Butter Substitutes

A Unidirectional DC-DC Autotransformer for DC Grid Application

Conventional unidirectional DC-DC converters for DC grid application employ DC-AC-DC two-stage conversion technology and suffer from high converter cost and power loss. To solve these issues, a unidirectional step-up DC-DC autotransformer (UUDAT) and a unidirectional step-down DC-DC autotransformer (DUDAT) are studied. The UUDAT and DUDAT are composed of a series connection of diode bridges and voltage source converters. Topologies of UUDAT and DUDAT are detailed. The harmonic and un-controllability issues are discussed. Control and possible application scenarios for UUDAT and DUDAT are depicted. DC fault isolation mechanism and the methods of dimensioning the voltage and power ratings of the components in UUDAT and DUDAT are studied. Extensive simulations on power system level and experiments on a UUDAT and DUDAT prototype verified their technical feasibility.

Технологія двостадійного фракціонування пальмової олії для виробництва замінників какао-масла

Технологія двостадійного фракціонування пальмової олії для виробництва замінників какао-масла

Two­stage treatment of solid waste leachates in aerated lagoons and at municipal wastewater treatment plants

The two-stage technology of treatment of the leachates of the municipal solid waste (MSW) dumps in aerated lagoons and at municipal wastewater treatment plants (WWTP) has been studied. The study objective was to develop a technology that can be implemented at existing MSW dumps and landfills. Static and dynamic modes of implementation of both stages of the technology were investigated on the model units. Static 16-day mode was experimentally studied in the aerated lagoon conditions. As a result, we have managed to achieve almost a 2-fold reduction of COD and more than a 3-fold decrease in concentration of ammonium ions. Dynamic mode studies have established that the optimal time of leachate staying in the reactor was 10 days. Change of the relative concentration of ammonium nitrogen in the leachate largely depends on the process temperature, so in real conditions, it is necessary to adjust the modes of realization of the individual stages depending on the ambient temperature. It has been established that for treatment of leachate at municipal WWTP in a static mode at the value of the ratio of leachate dilution with municipal sewage of 1:1000, the maximum effect of treatment of both from ammonium ions and COD was achieved. The study of leachate treatment at municipal WWTP in a dynamic mode has confirmed stability of maintaining the treatment indicators in time. By implementation of the two-stage technology of leachate treatment, it will be possible to minimize environmental hazard from surface and ground water contamination in the zone of influence of MSW dumps and landfills

Integrated Electrohydraulic Control Actuation System with Centralized Power Plant for the Reusable Launch Vehicle Technology Demonstrator

An electrohydraulic control actuation system for actuating eight aerodynamic control surfaces of the two-stage technology demonstrator of the Indian reusable launch vehicle (RLV-TD) was developed, validated by extensive testing in various test beds, simulation runs and flight proven in the RLV-TD HEX-01 mission flight on 23 May 2016. A centralized hydraulic power generating unit (HPU) was used for powering the eight actuators located in two stages. The network of plumbings and control components of this actuation system were required to be laid out over the entire length and breadth of the vehicle measuring 17 m in length, to distribute the hydraulic power to all the actuators. The hydraulic actuation system had to work for the longest ever duration of 833 s for an Indian launch vehicle. Many challenges arose due to a single HPU for two stages, long complex network of plumbings, longest ever operating duration, thermal issues, second-stage structure resembling an aircraft, limited occupancy for operations at the launch pad, limited power source, etc. Necessary provisions were incorporated in the design to successfully overcome them. This article describes the development of the control actuation system.

Automation for Crushing and Screening Equipment to Produce Graded Paving Crushed Stone

This paper offers analysis of factors related to production and storage of graded crushed stone, which adversely impact the service life and wear resistance of asphalt-concrete motor road pavements. The paper describes external and technology-related parameters that may cause changes of the preset ratio in graded crushed stone. Control factors are described that ensure the formulated fraction ratio in crushed stone by controlling the operation mode of the crushing and screening equipment. The paper also contains an ACS flow chart for crushing and screening equipment engaged in continuous closed-cycle two-stage technology. Performance of the ACS to maintain the preset fractionated crushed stone ratio has been confirmed with a mathematical model.

Evaluation of various cheese whey treatment scenarios in single-chamber microbial electrolysis cells for improved biohydrogen production

In this study single-chamber microbial electrolysis cells (MECs) were applied to treat cheese whey (CW), an industrial by-product, and recover H2 gas. Firstly, this substrate was fed directly to the MEC to get the initial feedback about its H2 generation potential. The results indicated that the direct application of CW requires an adequate pH control to realize bioelectrohydrogenesis and avoid operational failure due to the loss of bioanode activity. In the second part of the study, the effluents of anaerobic (methanogenic) digester and hydrogenogenic (dark fermentative H2-producing) reactor utilizing the CW were tested in the MEC process (representing the concept of a two-stage technology). It turned out that the residue of the methanogenic reactor – with its relatively lower carbohydrate- and higher volatile fatty acid contents – was more suitable to produce hydrogen bioelectrochemically. The MEC operated with the dark fermentation effluent, containing a high portion of carbohydrates and low amount of organic acids, produced significant amount of undesired methane simultaneously with H2. Overall, the best MEC behavior was attained using the effluent of the methanogenic reactor and therefore, considering a two-stage system, methanogenesis is an advisable pretreatment step for the acidic CW to enhance the H2 formation in complementary microbial electrohydrogenesis.

Microstructure, phase analysis and dielectric response of thin Pb(Zr,Ti)O3 films at the morphotropic phase boundary

The phase state of lead-zirconate-titanate thin films, obtained by a two-stage technology, at the morphotropic phase boundary is studied by electron backscatter diffraction and by measuring the temperature dependence of their dielectric constant. It is shown that depending on the working-gas pressure and the heat-treatment temperature, the volume ratio of the tetragonal and monoclinic modifications of the ferroelectric phase, which coexist at room temperature, varies. The nature of the observed variations is discussed.

Ультрабиомикроскопические параметры адекватного формирования путей оттока внутриглазной жидкости после непроникающей хирургии глаукомы

Purpose. To evaluate the ultra-bio-microscopic semiotics of internal fistula, which determines the time and indications for laser descemetopuncture after non-penetrating deep sclerectomy (NPDS), as well as a long-term hypotensive efficacy of this type of interventions. Material and methods. A full and recognized hypotensive effect was evaluated in 1000 patients with primary open-angle glaucoma after non-penetrating deep sclerectomy followed by laser descemetogoniopuncture. The group 1 included 500 patients (retrospective study), the group 2 – 500 patients (prospective study). All patients in the postoperative period underwent an ultrabiomicroscopic monitoring with an evaluation of parametric (mm) and morphometric (acoustic density) indices of internal fistula, intrascleral canal, and filtering bleb. Clinical groups were relevant to sex, age, stages of glaucoma and initial regimen of local hypotensive therapy. Follow-up period was 3 years. Results. The UBM semiotics for validity of the internal fistula are determined: a height of 0.8±0.09mm and a presence of micro-fistula after laser descemetopuncture. In the group 1: time of laser descemetopuncture was 3.4±1.9 months, a full hypotensive effect was observed in 59.6% 1 year later, in 24.8% after 3 years. In the group 2: time of laser descemetopuncture was 1.12±0.08 months, a total hypotensive success was determined in 84.8% after 12 months, up to 3 years – in 60.4% of cases. In its turn, an impact of NPDS hypotensive effect was associated with laser descemetogoniopuncture in 100% of cases 1-12 months after surgical stage of operation. Conclusion. The two-stage technology of non-penetrating deep sclerectomy with laser descemetopuncture in the absolute number of cases allows to create a penetrating internal micro-fistula and to exclude its influence on morphogenesis of newly formed aqueous humor outflow pathways. In its turn, it allows to increase a full and recognized hypotensive effect of fistulizing interventions of non-penetrating type.

ПРИМЕНЕНИЕ МЕТОДОВ БИОТЕХНОЛОГИИ В МЯСНОЙ ПРОМЫШЛЕННОСТИ

At present, to intensify the technological processes, to improve the organoleptic characteristics of products and to increase the output of the finished products we use multi-component brines at raw meat stuffing. All the components of the stuffing brines are cumulative and affect osmotic, diffusive and biochemical processes occurring in raw meat. Selecting the components of the brine with a directed action, it is possible to obtain a product of a specified quality. As all the components of the brine interact, this can lead to the uncontrolled process of salting; therefore one must pay attention to the development of technologies and formula of multi-component brines based on the properties of raw material and the brine ingredients. The purpose of the given research is to prove the selection of enzyme preparation for the production of whole muscle products as well as the development of the scheme for salting and ripening of raw materials, which takes into account the peculiarities of interaction between the brine ingredients. As a result of the analysis of the literature sources the enzyme preparation is selected which is balanced in the degree of impact on different meat proteins and works in the meat systems similar to the intracellular enzymes and has additional qualities that allow it to operate in a wider range of process parameters. Under experimental studies the two-stage technology of stuffing raw meat with the brine made from curd whey using a complex of proteoclastic enzymes has been proposed. The products developed on the basis of the given technology have very good organoleptic characteristics, and functional technological properties. Thus, the use of the two-stage curing in the production of whole-muscle products will improve the quality and the nutritional value, expand the range of products, and make it possible to use valuable raw meat comprehensively due to the possibility of adjusting its original properties.

Promising Technologies of Mining and Processing of Solid Minerals

The continuing growth in mineral extraction entails an increase in industrial waste, which in turn has a negative impact on the environment. Rubber-tired vehicles, in which the tires wear colossally, is mainly used as a transport for loading, unloading, transportation and other types of work in the extraction of solid minerals. The used tires are not disposed in any way, but are stored in special areas where harmful toxic substances are emitted under the influence of ultraviolet rays. Therefore, a decision was made to find a method for utilization and rational use of industrial waste in the road construction sector. The operating temperature of composite rubber-bituminous binders based on rubber crumb from the used automobile tires is estimated in this paper, which is necessary for assigning technological parameters of production and laying of asphalt-concrete mixtures produced on their basis. It is established that composite rubber-bituminous binders based on rubber chips from the used automobile tires, produced according to the two-stage technology, have the same viscosity as the original petroleum bitumen, at a temperature increased by 20°C.

An autonomous underwater vehicle positioning matching method based on iterative closest contour point algorithm and affine transformation

An improved autonomous underwater vehicle federal integrated navigation method based on two-stage position matching technology is proposed in this study to solve the problem of positioning divergence caused by the defects of error accumulation in an inertial navigation system. The improved two-stage position matching method includes the acquisition and preprocessing of the strap-down inertial navigation system and indicates track sequences and elevation measurement sequences. The first-stage position matching is based on iterative closest contour point, while the second-stage position matching is based on an affine algorithm. Simulation results indicate that the proposed algorithm solves the problem of the limitation of the rigid transformation of traditional iterative closest contour point and effectively resolves the matching failure caused by the large initial position error of long-time navigation.

Role of organic loading rate in bioenergy generation from palm oil mill effluent in a two-stage up-flow anaerobic sludge blanket continuous-stirred tank reactor

This contribution presents the technical possibilities for continuous hydrogen and methane production using an optimum organic loading rate of palm oil mill effluent in a two-stage reactor at a thermophilic temperature of 55 °C. The influence of four organic loading rates, namely, 30, 40, 50, and 60 kg COD/(m3 d) for hydrogen production and 8.3, 10.2, 13.1, 15.8 kg COD/(m3 d) for methane production, were investigated. Hydrogen production was controlled in an up-flow anaerobic sludge blanket reactor at a constant hydraulic retention time of 12 h. The maximum hydrogen content, volumetric hydrogen production rate and hydrogen yield were found to be 45%, 2.5 L H2/d and 33.48 mL H2/g COD, respectively, at the organic loading rate of 50 kg COD/(m3 d). The effluent from the hydrogenogenic reactor was further digested into methane in the continuous stirred tank reactor at a hydraulic retention time of 5 d. The maximum volumetric methane production rate and methane yield were 10.58 L CH4/d. and 0.11 m3 CH4/kg COD, respectively, at an organic loading rate of 13.1 kg COD/(m3 d). A total chemical oxygen demand removal of 91% was achieved in this two-stage process. The scientific contribution of this two-stage technology with an optimized organic loading rate may play a significant role in degrading palm oil mill effluent and developing an energy-efficient strategy for waste management.

A database and workflow integration methodology for rapid evaluation and selection of Improved Oil Recovery (IOR) technologies for heavy oil fields

Conventional crude oil is the currently dominant but a non-renewable energy resource. Despite the development and improvement of alternative energy technologies, there is still a large gap between the capability of renewable energy systems to capture and reliably supply power, and the ever-increasing global energy demand requirements. Therefore, until technological innovations facilitate sufficient energy generation through alternative fuels, other means of sustaining crude oil production, such as Improved Oil Recovery (IOR) methods, must be systematically explored. Beyond increasing production of conventional oil, IOR methods can effectively facilitate the extraction of oil from unconventional reservoirs, such as heavy oil fields. This capability is of high strategic importance due to the considerably large size of global heavy oil reserves.There are several IOR technologies available, but each of them is suitable only for certain oil field types. The aim of this paper is to illustrate an alternative, low-cost, quick screening method which is competitive to more technically laborious and costly methods for selecting the most suitable technology for a given heavy oil extraction project, using a limited dataset. A two-stage technology screening method is hereby proposed: the first stage is based on previous project literature data evaluation, and the second stage is based on simple empirical oil production correlation methods (such as the Marx & Langenheim model) coupled with Ingen's RAVE (Risk and Value Engineering) and Schlumberger's PIPESIM software applications. The new method can achieve reasonably accurate results and minimise cost and time requirements during the preliminary stages of an oilfield development project, as evidenced via a comprehensive case study.

Investigation of mechanical and electrical properties of Li doped sodium niobate ceramic system

ABSTRACTThe Na0.96Li0.04NbO3 ceramic solid solution was prepared by means of a two-stage hot-pressing technology. The X-ray diffraction analysis showed the formation of a single perovskite phase with an orthorhombic symmetry in the investigated composition. The microstructure and EDS measurements were performed. They confirmed the high purity and the expected qualitative composition. A good homogeneity of the microstructures and a small degree of porosity were observed. The elastic modulus (the Young's modulus E, shear modulus G, and Poisson's ratio ν) of Na0.96Li0.04NbO3 were determined with the use of an ultrasonic method. The electrical properties of Na0.96Li0.04NbO3 ceramics were investigated at the frequency ranging from 0.5 kHz to 200 kHz, and the temperature ranging from room temperature to 750 K. The test sample shows a dielectric dispersion.